Renowned actor Philip Seymour Hoffman was found dead in his Greenwich Village apartment Sunday of an apparent heroin overdose. His performances, whether in a lead or a supporting role, touched audiences.

Perhaps that was part of his charm, what made it possible for him to so believably slip into the skin of doting hospice nurse Phil Parma in “Magnolia,” the tragically defeated salesman Willy Loman in a stage production of “Death of a Salesman,” and hot-tempered gruff Gust Avrakotos in “Charlie Wilson’s War.”

And perhaps that is why the American public has taken his death this Sunday so personally.

Hoffman's unwavering devotion to his craft brought three-dimensional humanity to every role he played, from supporting character to leading man. But like many other great artists, he struggled with and eventually succumbed to addiction, according to law enforcement officials who reportedly found Hoffman in his Greenwich Village home in New York with a syringe in his arm and several glassine envelopes containing what is believed to be heroin.

Shortly after graduating from New York University’s Tisch School of the Arts, Hoffman become mired in substance abuse, he told Steve Kroft in a 2006 interview for "60 Minutes."

“I liked it all,” he told Mr. Kroft. "I went [to rehab], I got sober when I was 22 years old. You get panicked ... and I got panicked for my life."

Hoffman reportedly returned to rehab in May 2013, when a prescription-drug problem escalated to a return to heroin use. He went back to work after a 10-day stint in a detox treatment program.

He attended the Sundance Film Festival in Park City, Utah, last month, promoting his newest film, “A Most Wanted Man,” scheduled for release later this year.

Those close to Hoffman said they believed he had overcome his most recent battle with addiction.

“I saw him last week, and he was clean and sober, his old self,” David Bar Katz, the friend who found Hoffman in his bathroom on Sunday, told The New York Times. “I really thought this chapter was over.”

"We spent some time together only two weeks ago and he seemed in a good place, despite some issue he had to deal with," Anton Corbijn, director of "A Most Wanted Man,” told the Los Angeles Times.

Hoffman’s death is the latest in long line of artistic lights snuffed out by addiction. "Glee" star Cory Monteith overdosed on a combined concoction of heroin and alcohol in July 2013. That same month, Chris Kelly, a former member of the 1990s rap duo Kris Kross, overdosed on heroin and cocaine. Drugs may have been involved in the 2012 drowning of pop-diva Whitney Houston and played a role in the 2008 death of actor Heath Ledger.

Hoffman was 46 and is survived by Mimi O'Donnell, his longtime partner, and their three children.

[Editor's note: An earlier version of this story included an incorrect spelling of the fictional character Willy Loman and incorrectly identified the timing of Mr. Hoffman's appearances at the Sundance Film Festival.]